 
<template>

  <div class="goods-image">
    <!-- 左侧大图-->
    <div
      class="middle"
      ref="target"
    >
      <img :src="imageList[activeIndex]">
      <!-- 蒙层小滑块 -->
      <div
        class="layer"
        v-show="!isOutside"
        :style="{left:`${left}px`,top:`${top}px`}"
      > </div>
    </div>
    <!-- 小图列表 -->
    <ul class="small">
      <li
        v-for="(img,i) in imageList"
        :key="i"
        @mouseenter="enterhandler(i)"
        :class="{active:i === activeIndex}"
      >
        <img
          :src="img"
          alt=""
        >
      </li>
    </ul>
    <!-- 放大镜大图 -->
    <div
      class="large"
      v-show="!isOutside"
      :style="[
        {
            backgroundImage:`url(${imageList[0]})`,
            backgroundPositionX:`${positionX}px`,
            backgroundPositionY:`${positionY}px`
        }
      ]"
    >

    </div>
  </div>
</template>

 <script setup>
import { ref, watch } from "vue";
import { useMouseInElement } from "@vueuse/core";
// 1.小图切换大图显示
const activeIndex = ref(0);

// 图片列表适配
defineProps({
  imageList: {
    type: Array,
    default: () => [],
  },
});
// 图片列表
// const imageList = [
//   "https://yanxuan-item.nosdn.127.net/e07c2b63765cf9f4a46d489c6e09c1c1.jpg",
// ];
const enterhandler = (i) => {
  activeIndex.value = i;
};

// 2,vue-use获取鼠标相对位置
const target = ref(null);
const { elementX, elementY, isOutside } = useMouseInElement(target);

// 3.控制滑块距离  监听 elementX/Y 变化设置 left /top

const left = ref(0);
const top = ref(0);
let positionY = ref(0);
let positionX = ref(0);
// 监听小图变化
watch([elementX, elementY], () => {
  console.log("xy变化了");
  //   优化 如果鼠标没有移入盒子里面 不执行后面逻辑
  if (isOutside.value) return;
  console.log("后续逻辑执行了");
  //   控制有效范围
  // 横向
  if (elementX.value > 100 && elementX.value < 300) {
    left.value = elementX.value - 100;
  }
  //   纵向
  if (elementY.value > 100 && elementX.value < 300) {
    top.value = elementY.value - 100;
  }
  //   处理边界
  if (elementX.value > 300) {
    left.value = 200;
  }
  if (elementX.value < 100) {
    left.value = 0;
  }
  if (elementY.value > 300) {
    top.value = 200;
  }
  if (elementY.value < 100) {
    top.value = 0;
  }

  //   控制大图的显示
  positionX.value = -left.value * 2;
  positionY.value = -top.value * 2;
});
</script>
<style scoped lang="scss">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
  }

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    z-index: 500;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    // 背景图:盒子的大小 = 2:1  将来控制背景图的移动来实现放大的效果查看 background-position
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .layer {
    width: 200px;
    height: 200px;
    background: rgba(0, 0, 0, 0.2);
    // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
    left: 0;
    top: 0;
    position: absolute;
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid $xtxColor;
      }
    }
  }
}
</style>